Monarch Butterflies with Darker Wings Fly Farther
For Monarch butterflies, redder is better. That is, the darker their wings, the better they are able to fly, according to a new study published in PLoS ONE.
The subtle differences in color between butterflies have biological significance, warning predators of their bitter taste and toxicity and even distinguishing between migratory and non-migratory butterflies, which suggests an association between darker color and increased insect fitness, reports The Daily Mail.
Like Us on Facebook
Andrew Davis of the University of Georgia sought to test whether the colors of the butterfly rainbow may be associated with their flight abilities. To test this, he and his colleagues set up a butterfly treadmill of sorts, in which 121 monarch butterflies circled the test area while researchers measured the speed, duration and distance of their flights.
Each butterfly was fitted with a tiny wire glued to its back between its wings, which connected to a light carbon rod with a flag that passed through a 'photogate' to record each lap made by the Monarch. The apparatus was balanced according to the butterfly's weight, so as not to disturb its flight.
They found that the average flight time was about an hour, but butterflies with darker orange wings flew longer distances than those with wings of a lighter color.
"Butterfly researchers don't often look closely at color variation between individuals of the same species. The results of this project will pave the way for a new line of inquiry into the significance of butterfly wing color," Davis said.
Summer is breeding season for North American Monarch butterflies, and some of these winged insects later migrate south to Mexico for the winter.
A couple of years ago Davis had been catching migrating butterflies and he noticed their wings had a much darker color orange than he was used to, reports ABC Science.
He systematically compared the color of the wings of individuals captured during the summer breeding season with those of individuals captured during the autumn migration.
"The monarch captured in the fall [autumn] were statistically darker than those captured in the summer," says Davis. That's what inspired him to test whether the color of the butterflies had any correlation with their ability to cover long distances in flight.
"We still don't know why there is this link between color and flight performance," he told ABC Science. "For us and for a lot of other scientists I think this is going to be new territory."
© 2012 iScience Times All rights reserved. Do not reproduce without permission.